Emergency shutoff device



Feb. 14, 1950 R. SHEPPARD 2249"?,6951

EMERGENCY SHUTOFF DEVICE Filed Jan. 22, 1944- H is Attorh ey.

Patented Feb. 14, 1.950

EMERGENCY SHUTOFF DEVICE Raymond Sheppard, Niskayuna, N. Y., assigner toGeneral Electric Company, a corporation of New York Application January22, 1944, Serial No. 519,305

'l Claims. (Cl. 137-139) The present invention relates to lubricating orliquid supply systems for turbines or like machines. More specifically,the invention relates to the kind of lubricant or liquid supply systemswhich include a tank or container for lubricant or liquid arranged at alevel above that of the turbine bearing or consumer to feed lubricant tosuch turbine bearing or consumer by gravity together with means forshutting down the turbine or like machine associated with the consumerwhenever the liquid supply from the tank or reservoir is endangered,that is, when the liquid in the reservoir reaches a certain low level.Heretofore it has been the practice to provide an emergency mechanismconnected by a riser to the reservoir and adapted to disconnect theturbine or like machine upon a certain drop of the liquid level in thereservoir. Difficulties have been experienced with these arrangements inthe refilling of the riser pipe due to the accumulation of air therein,which often makes it dicult, if not impossible, to reset the mechanism.

The object of my invention is to provide an improved construction andarrangement of lubricating or liquid supply systems of the type abovespecified whereby the aforementioned ditiiculties are overcome and theemergency mechanism may be readily reset.

This is accomplished in accordance with my invention by the provision ofmeans including a liquid supply conduit connected to the lower end ofthe riser pipe to iill the latter from its lower end thus precluding theentrapping of air in said pipe during the resetting of the emergencymechanism.

For a better understanding of what I believe to be novel and myinvention, attention is directed to the following description and theclaims appended thereto in connection with the accompanying drawing.

The single ligure ot the drawing illustrates a lubricant or liquidsupply system embodying my invention in connection with an elastic fluidturbine.

The arrangement as shown in the drawing comprises an elastic iluldturbine I0 having a shaft Il supported on a bearing I2 and an inletconduit i3 for conducting elastic iiuid to the turbine. 'I'he iiow ofiluid through the conduit Il is controlled bycontrol valve means I4. Athrottle or emergency shut-oi! valve I5 is arranged in the conduit 'I3ahead of thecontrol latch IB normally to hold the valve l5 in fully openposition against the biasing force of a spring I9. Upon removal oi thelatch I8, the valve I5 is shut by action of the spring I9. A tank orreservoir 20 located at a level above that of the turbine is connectedby a conduit 2| with branches 22, 23 to the bearing l2 and otherldesirab to maintain a nquid 1eve1 2s in the tank' 20. If due to failureof the pump 26 or the power agency 2l or orany other reason the liquidin the tank drops to a predetermined level 29 which is considered unsafeit is desirable automatically to shut down the turbine i0. While thereis still a substantial amount of liquid contained inthe tank 20 at thelevel 29, such liquid or lubricant is needed especially for the bearvings l2 in view of the considerable time it may take for the turbine toreach standstill upon shutting oli the elastic fluid supply to theturbine.

The arrangement for shutting down the turbine upon the liquid in thetank 22 reaching the unsafe level 29 comprises an emergency speed valveI4 as regards the direction of iiow of duid governing mechanism 30responsive to emergency speeds of the turbine lil and an auxiliarymechanism `3l responsive to certain changes of the liquid level in thetank 20.

The emergency governing mechanism 30 lncludes a bell-crank 32 supportedon a fulcrum 33 and having one arm formingthe aforementioned latch I8and another arm connected to the upper end of a stem 34 which at itslower end is secured to a piston 35 movably disposed in a hydrauliccylinder 36 biased downward by a spring 3l. Fluid under pressure, suchas oil, is supplied to the lower end o the cylinder 3B by a conduit 38connected to a valve casing u forming two chambers 40 and 4| withopenings controlled by valves 42 and 43 respectively secured to a stem'44. Operating iluid under pressure is supplied to the chamber 40 bymeans including a pumpy 45. In the position shown the valve 40 is openand valve l43 is closed, thus connecting the chambers 40, 4l in seriesbetween `the pump 45 and the conduit 38. When the position of the valves42, 43 is reversed. the chamber 4| is disconnected from the duid supplyand iluid contained in the chamber 4I and the hydraulic motor 86 isdischarged through the open valve 43.

The valves 42, 43 normally are held in the position shown by means of alatch 46 secured to the intermediate portion of a lever 41 supported ona fulcrum 38 and biased into the position shown by a spring 49 against astop 50. An upper portionof the lever 41 is associated with an emergencyspeed governor which has a fiyweight 52 biased inward againstcentrifugal force by a spring 53. During operation the ilyweight 52 isforced outward by centrifugal force as the turbine reaches emergencyspeed whereby the lever 41 is engaged by the fiyweight 52 and turnedcounter-clockwise, thus removing the latch 46 from the end of the stem44 and causing the latter to -be forced towards the right by the actionof a compression spring 54. The mechanism so far described is typical ofany emergency governing niechanism to close a kthrottle valve atemergency speed of a prime mover or like machine.

The auxiliary mechanism for effecting closing of thedthrottle valvebelow a safe level of the liquid in the tank 20 according to myinvention comprises a pressure responsive device which in the presentinstance is in the form of a hydraulic motor having a cylinder 55 with apiston 56 slidably disposed therein and connected to a stem 51. Theright-hand end of the stem 51 is connected to the lower end of a lever58 having an intermediate point supported on a fulcrum 59 and an upperend cooperatively associated with a rod 60 slidably held on spacedbearing supports 6|, 62. The rod 60 is biased towards the left by aspring 63 bearing at one end against a spring plate 64 secured to therod 60 and at the other end against a ilxed abutment 65. The righthandend of the rod 60 is cooperatively associated with the lever 41.` Uponclockwise movement of the lever 58 the upper end thereof engages anabutment 66 secured to the rod 68, forcing the latter to the right andthus causing counterclockwise turning movement of the lever 41 andremoval of the latch 46 from the right-hand end of the stem 44 wherebythe latter is forced to the right, causing closing of thevalve 42 andopening of the valve 43 in the manner described above.

The piston 56 is biased towards the left by a compression spring 61against -the fluid pressure in a chamber 68 formed on the left-hand sideof the piston-56 in the cylinder 65. This chamber 68 is connected toreceive fluid under pressure through a riser pipe 69 which has an upperopen end portion or vent above the tank 28. The riser pipe isI.connected to the tank to receive liquid therefrom through /a conduit1| which in the present instance is connected to the aforementionedlsupply conduit 2| and has an upper horizontally extending portion 12loto the level- 29. the level in the riser conduit 69 will rapidly dropdue to the continued discharge of liquid through the bleed-oil.' pipe13. As the pressure inthe chamber 68 reaches a certain minimum due tothe low static pressure of the liquid column in the riser conduit 69 thepiston 56 is forced to the left by action ofthe spring 61, thus causingunlatching of the latch 46 and reversing of the position of theemergency valves 42, 43, resulting in closing of the throttle valve I6.

If thereupon the necessary repairs have been made and liquid such as oilis again supplied from the pump 26 to the tank 20, it becomes cated atthe level 29 in the tank 20. Hence liquid is supplied from the tankthrough the conduit V .and normally a continuous flow of liquid from thetank 2|) through the conduit 69, 12 and the vchamber 68 takes place.Upon interruption of such supply, as when the liquid in the tank 20drops necessary to reset the main and auxiliary mechanisms 38, 3|. Ithas been found that the refilling of the riser pipe 69 from the tank 20is undesirable because in many instances a substantial amount of air isyentrapped in the riser conduit 69 so that the pressure in the chamber 68does not rise suiliciently to force the piston 56 to the right to permitrelatching of the latch 46. These difficulties are overcome by myinvention by the provision of means for refilling the riser conduit 69from its lower end. To this end the casing 39 of the emergency governingmechanism is provided with an extension 14 flanged to its left-hand endand having a cylindrical bore 15. Two pistons 16 and 11 are slidablydisposed in the cylindrical bore 15 and attached to an extension of thestem 44 to form with the bore an annular chamber 18. This chamber isconnected by a conduit 19 to the pressure chamber 68 in the cylinder 55.The extension 14 with the piston 11 broadly constitutes a valve fornormally disconnecting the pressure chamber 68 from the chamber 40,which latter constitutes a source of liquid under pressure.

During operation the piston 56 is forced to the left as the liquid inthe tank 20 drops below the level 29, thus causing unlatching of thelatch 46 and reversing of the positions of the valves 42, 43 from thatshown in the drawing. Upon closing of the valve 42 the piston 11 ismoved into the chamber 48 whereby the latter is put into communicationwith the annular chamber 18. This causes supply of liquid under pressurefrom the pump 45 through the chambers 40, 15 and the conduit 19 to thechamber 68. The liquid is forced from the chamber 68 through theconduits 69 and 1|. Thus the conduit 69 is filled from its lower end,eliminating the danger of air being entrapped in the conduit 69 andassuring that "the proper pressure is established in the pressurechamber 68 as the liquid in the conduit 69 reaches the level 29. Thus,immediately upon actuation of the auxiliary governing mechanism thelatter is automatically reset by the supply of uid under pressure to thechamber 68 from the chamber 48. The turbine then may again be placed inoperation by opening the throttle valve |6 and positioning the valves42, 43 as shown in the drawing. To this end the left-hand end of thestem 44 is provided with a knob or handle 88, permitting resetting bypulling the handle towards the left against the force of the biasingspring 54. As this is done the latch 46 is forced into the positionshown by action of the biasing spring 49.

What I claim as new Letters Patent of the United States is:

1. In a liquid distribution system, the combination of a tank forcontaining liquid, a presv sure responsive 'device located at a levelbelow the tank and including a pressure chamber withy a bleed port andacontrol member subject to and desire to secure byv the pressure in thechamber and arranged to move from a normal tovan emergency position inaccordance with changes in said pressure, means biasing the controlmember to emergency position, a standpipe arranged to conduct liquidfrom the tank to the chamber by gravity at a rate to maintain thechamber continuously full and to exert a pressure on the control memberto retain it in the normal position as long as the liquid in the tank isabove a predetermined level, the bleed port being arranged to empty thestandpipe and pressure chamber when the supply of liquid from the tankto the standpipe ceases, and means for automatically refilling thestandpipe and pressure chamber with liquid upon occurrence of a certaincritical drop of the liquid level in the standpipe below saidpredetermined level, said relling means comprising a source of liquidunder pressure, a conduit connected between said source and chamber, avalve in the conduit, means biasing the valve toward open position,latching means normally holding the valve in closed position, and meansassociated with the control member for unlatching the latching means inresponse to a predetermined pressure change in the chamber correspondingto said critical drop in the level of liquid in the standpipe.

2. In a hydraulic system, a tank for containing liquid, a liquid levelresponsive device located at a level below the tank and including aliquid motor with a pressure chamber and a pressure sensing memberhaving a normal and an emergency position, a bleed port arranged toempty the pressure chamber when the flow of liquid to the motor isdiscontinued, a standpipe and a conduit arranged to conduct liquid fromthe standpipe to the chamber at a rate to maintain the chambercontinuously full and to exert a pressure on the pressure sensing memberto retain it in normal position as long as the standpipe contains liquidto a iirst predetermined level, a conduit for supplying liquid from thetank to the standpipe and having a highest portion located at a levelcorresponding to a predetermined critical level of liquid in the tank,said conduit being so arranged that the iiow of liquid from the tank tothe standpipe is discontinued when the level of the liquid in the tankfalls below said predetermined critical level, biasing means arranged tomove the pressure sensing member from normal to emergency position whenthe level of liquid in the standpipe falls below said iirstpredetermined level, and means including a source of liquid underpressure, a distributing valve, and a conduit for refilling thestandpipe from its lower end to preclude air and foam being entrappedtherein during the relling operation.

3. In a liquid level responsive device, the combination of a controlmember having a normal position and an emergency position, means biasingthe member to emergency position and retaining means for holding themember in normal position, a standpipe with means for supplying liquidthereto at a variable rate, a iiuid pressure motor having a normal andan emergency position and arranged to release the retaining means whenmoved to emergency position, means biasing the motor to emergencyposition, conduit means arranged to supply liquid from the bottom of thestandpipe to the motor at a rate suillcient to maintain the motorcontinuously full of liquid and to exert a pressure therein to hold itin normal position as long as the liquid in the standpipe is above apredetermined level, a bleed port arranged to drain the motor andstandpipe when the supply of liquid thereto is insumcient, means forsupplying liquid under pressure, a distributing valve associated withthe control member and constructed and arranged so that liquid underpressure passes from the supply means to the motor and to the standpipewhen the control member is in emergency position, and means forresettingthe control member to normal position.

4. In a liquid level responsive device the combination of a controlmember having a normal position and an emergency position, means biasingthe member to emergency position and retaining means for holding themember in normal position, a standpipe with mians for supplying liquidthereto to a variable level, a ilrst iluid pressure motor arrangedltoactuate an operating member, a second iluid pressure motor having anormal and an emergency position and arranged to release the retainingmeans when moved to emergency position, means biasing the second motorto emergency position, conduit means connected to supply liquid underpressure from the standpipe to the second motor whereby said motor ismaintained against the biasing means in normal position as long as theliquid in the standpipe is above a predetermined level, means forsupplying liquid under pressure, a distributing valve associated withthe control member and constructed and arranged so that liquid underpressure passes from the supply means to the rst motor when the controlmember is in normal position and from the 'supply means to the secondmotor and to the standpipe when the control member is in emergencyposition, valve means associated with the control member constructed andarranged to exhaust said pressure liquid from the first motor when thecontrol member is in emergency position, and means for resetting thecontrol member to normal position.

5. In combination with a liquid reservoir, a standpipe having a iirstupper portion communieating with the reservoir and a second lowerportion communicating with a liquid level responsive device below thereservoir, said iirst portion being arranged to supply liquidcontinuously to the standpipe as long as the level of the liquid in thereservoir is above a predetermined level, a conduit connected to theupper portion of the standpipe and having a vent to atmosphere at apoint above the highest level of liquid in the reservoir, the liquidlevel responsive device including a control member having a normalposition and an emergency position, means biasing the member toemergency position and retaining means for holding the member in normalposition, a uid pressure motor having a normal and an emergency positionand arranged to release the retaining means when moved to emergencyposition, means biasing the motor to emergency position, said motorbeing maintained in its normal position against its biasing means solong as the liquid in said reservoir is at a level above saidpredetermined level, means for supplying liquid under pressure, adistributing valve associated with the control member and constructedand arranged so that liquid under pressure passes from the supply meansto the iluid pressure motor and to the lower end of the standpipe whenthe control member is in emergency position, a bleed port arranged todrain liquid from the motor and the standpipe, and means for resettingthe control member to normal position.

6. In combination with a liquid reservoir. a control device including anoperating member, a ilrst iluid pressure motor having a normal and anemergency position and arranged to actuate the operating member, meansbiasing the first motor toward the emergency position, means forsupplying liquid under pressure, a control member having a normal and anemergency position, a distributing valve associated with the controlmember constructed and arranged so that liquid under pressure will flowfrom the supply means to the rst motor to maintain said iirst motor inits normal position when the control member is in normal position, valvemeans associated with the control member constructed and arranged sovthat the liquid under pressure will exhaust from said first motor whenthe control member is in emergency position, means biasing the controlmember to emergency position and retaining means for holding it innormal position, a second iiuid pressure motor yhaving a normal positionand an emergency position and arranged to release the retaining meanswhen moved to emergency position, means biasing the second motor toemergency position, conduit means communieating to the second motor avariable pressure which is suiilcient to maintain the second motor innormal position against said biasing means when the liquid in thereservoir is above a predetermined minimum level, the distributing valveassociated with the control member being also arranged to supply liquidunder pressure to the second motor to restore it to normal position whenthe control member is in emergency position, and means for restoring thecontrol member to normal position to cut oil.r the ilow of liquid to thesecond motor and supply liquid under pressure to the first motor torestore it to normal position.

'7. In combination with a pressure liquid supply source, a controldevice including an operating member, a first uid pressure motor havinga normal and an emergency position and arranged to actuate the operatingmember, means biasing the first motor toward the emergency position,

a distributing valve having a normal and ai! emergency position andconstructed and arranged when in normal position to eect the now oiliquid under pressure from supply means to the iirst motor to maintainsaid iirst motor in its normal position, an exhaust valve associatedwith said distributing valve constructed and arranged to effect the flowof pressure liquid from said iirst motor when the distributing valve isin emergency position, means biasing the distributing and exhaust valvesto emergency position and retainf ing means adapted to hold the valvesin normal position against the force of the biasing means, a secondiiuid pressure motor having a normal and an emergency position, meansbiasing ,the second motor to emergency position, conduit meanscommunicating liquid from the supply source to the second motor tomaintain it in normal position against said biasing means when thepressure of said liquid from said 4source is above a predeterminedvalue. means associated with the second motor to release the retainingmeans when the second motor moves to emergency position, conduit meansarranged to conduct liquid under pressure from the distributing Valve tothe second motor when the distributing valve is in emergency position toreset the second motor to normal position, and means for resetting thedistributing and exhaust valves from emergency position to normalposition to again effect the iiow of liquid under pressure 'from thesupply to the iirst motor to reset it to normal position.

RAYMOND SHEPPARD.

REFERENCES CITED The following references are oi' record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,401,239 Cockburn Dec. 27, 19211,934,631 Taylor Nov. 7, 1933 2,099,556 Carpenter Nov. 16, 1937

